June 1912: Passengers on the promenade deck of the RMS Lusitania. (Photo by Topical Press Agency/Getty Images)

Passengers relax in deckchairs on the saloon deck of the Cunard liner Lusitania, June 1912. The ship was sunk by a German submarine in 1915. (Photo by Topical Press Agency/Hulton Archive/Getty Images)

circa 1914: The British steamship, 'Lusitania' sunk by a German submarine on the 7th May 1915 with the loss of 1198 lives. (Photo by Topical Press Agency/Getty Images)

circa 1910: British liner the 'Lusitania', which was sunk off Kinsale on the Irish coast by a German U-boat in 1915. (Photo by Hulton Archive/Getty Images)

May 1915: In an old churchyard in Queenstown, Ireland soldiers dig graves for the victims of the Lusitania disaster. The Lusitania was a Cunard passenger liner sunk by a German U-boat in the Irish sea. (Photo by Topical Press Agency/Getty Images)

May 1915: A graveside service for the victims of the Lusitania disaster, the British passenger liner which was sunk off the coast of Kinsale by a German U-boat in 1915. (Photo by Topical Press Agency/Getty Images)

May 1915: Funeral cortege in Queenstown of the victims of the Lusitania disaster. The Lusitania was a Cunard passenger liner sunk by a German U-boat in the Irish sea with a great loss of life. (Photo by Topical Press Agency/Getty Images)

Servicemen attend the mass funeral in Cobh, County Cork of the victims of the Lusitania disaster. The Cunard liner was torpedoed by a German submarine off the coast of Ireland and sank with the loss of 1,198 lives. (Photo by Topical Press Agency/Getty Images)

May 1915: Survivors of the Lusitania disaster. (Photo by Topical Press Agency/Getty Images)

Shocked survivors of the 'Lusitania' disaster, brought ashore at Cobh, County Cork. The passenger liner was carrying war supplies and sunk by enemy action with great loss of life. (Photo by Topical Press Agency/Getty Images)

Survivors of the Cunard passenger liner, the Lusitania, that was sunk by the German Navy off the South Coast of Ireland. (Photo by Topical Press Agency/Getty Images)